Hemorrhage control devices and methods

ABSTRACT

Embodiments herein comprise a hemostatic composition comprising a plurality of liquid expandable articles capable of expanding upon contact with a liquid. A suitable composition comprises a plurality of liquid-expandable articles that may be mechanically uncoupled from one another and therefore may be capable of moving independently from one another. The plurality of liquid-expandable articles may comprise a compressed material capable of a high-degree of expansion upon liquid contact.

RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.12/773,680, now U.S. Pat. No. 8,828,050 (issued on Sep. 9, 2014), filedMay 4, 2010, which claims the benefit of U.S. Provisional ApplicationNo. 61/215,377, filed May 4, 2009, U.S. Provisional Application No.61/277,117, filed Sep. 18, 2009, and U.S. Provisional Application No.61/310,075, filed Mar. 3, 2010, the contents of all of which areincorporated herein by reference in their entireties.

FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

This invention was made with United States government support pursuantto various contracts from the United States Special Operations Command.The United States may have certain rights to this invention.

TECHNICAL FIELD

Embodiments of the present invention relate to methods, compositions anddevices for controlling bleeding and treating wounds.

BACKGROUND

A leading cause of preventable battlefield death is non-compressible,intracavitary bleeding. Projectiles from weapons and improvisedexplosive devices frequently create small entrance wounds having limitedor no visibility to the sites of non-compressible, intracavitarybleeding. Although several wound dressing technologies are beingmarketed to control aggressive hemorrhages from severe externalinjuries, these devices are particularly ineffective againstnarrow-entry wounds and the survival of the soldier is entirelydependent on immediate access to blood products and emergent surgicalrepair.

A principal method for treating bleeding wounds is to stop the flow ofblood by applying pressure with a bandage to facilitate formation of aclot. Current wound dressings are often too stiff and too rigid to fitinto a narrow space of a cavity wound or, if sufficiently pliable, donot adequately conform to irregular tissues geometries to cause rapidand effective hemostasis.

Granular and powder based hemostatic products have been employed toaddress the deficiency of current wound dressing for non-compressiblewounds, however, these products also have significant drawbacks.Hemostats in the form of powders, particulates or granules pose anunacceptable risk in forming emboli, are difficult to deploy in austereenvironments (e.g., environments that include wind, darkness, etc.), aresusceptible to washing or migration away from the wound site, and aredifficult to retrieve from the wound site at a place of definitive care.Additionally, granular and powder based hemostatic products aredifficult to handle because they may have high electrostatic chargecausing them to stick to instruments, gloves and tissues, thuspreventing adequate penetration into irregular wound cavities. Also, inwindy environments, powders or granules may be very difficult to getinto the wound and may actually blow back into a caregiver's eyes.Powder or granule based hemostats also exhibit a lack of physicalcohesion, making them unable to sufficiently withstand the chaotic fluidenvironments created by severe, high pressure bleeding. Thus, thesegranular and powder based hemostats may simply wash away beforeeffectively contributing to hemostasis.

Accordingly, there remains a need for a more effective way to treatnon-compressible hemorrhagic injuries.

SUMMARY

In a first aspect, the invention is directed to a hemostatic compositioncomprising a plurality of liquid expandable articles capable ofexpanding upon contact with a liquid.

In a second aspect, the invention is directed to a medical devicecomprising the composition of the first aspect with an applicator. Theapplicator facilitates the storage, handling and deployment of thecomposition of the first aspect.

In a third aspect, the invention is directed toward a method to effectrapid hemostatic response and control hemorrhage by introducing thecomposition of the first aspect into a bleeding wound cavity.

In a fourth aspect, the invention provides a method of preparing acomposition in accordance with the first aspect of the invention.

In a fifth aspect, the invention provides a method of preparing amedical device in accordance with the second aspect of the presentinvention.

The invention is also directed to, in combination, a living being havinga body with a wound defining a cavity with a volume bounded by a surfacethrough which blood is flowing into the cavity, the cavity having anentry opening that is in communication with the cavity; and a pluralityof expandable articles that each have a starting volume and a secondvolume that is greater than the starting volume, the plurality ofexpandable articles with the starting volume deliverable through theentry opening into the cavity and upon being exposed to fluid in thecavity expanded to the second volume, the plurality of expandablearticles within the cavity and expanded to the second volumecollectively inducing hemostasis.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention will be readily understood by thefollowing detailed description in conjunction with the accompanyingdrawings. The present invention will be described by way of exemplaryembodiments, but not limitations, illustrated in the accompanyingdrawings in which like references denote similar elements, and in which:

FIGS. 1A-1C illustrate embodiments of a hemostatic composition inaccordance with the first aspect of the present invention.

FIGS. 2A-2B illustrate further embodiments of a hemostatic compositionin accordance with the first aspect of the present invention.

FIG. 3 illustrates further embodiments of a hemostatic composition inaccordance with the first aspect of the present invention.

FIG. 4 illustrates a device according to the second aspect of theinvention.

FIG. 5 illustrates embodiments of a device according to the secondaspect of the invention.

FIG. 6 illustrates further embodiments of a device according to thesecond aspect of the invention.

FIG. 7 is illustrative of treating a wound with a composition accordingto the first aspect of the invention.

FIGS. 8A-8B illustrate a method for treating a bleeding wound employingthe hemostatic compositions in accordance with embodiments of the firstaspect of the present invention.

FIG. 9 is illustrative of the preparation of a composition according tothe first aspect of the invention.

FIG. 10 is illustrative of preparing a device according to the secondaspect of the invention.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

In the following detailed description, reference is made to theaccompanying drawings which form a part hereof wherein like numeralsdesignate like parts throughout, and in which is shown by way ofillustration embodiments in which the invention may be practiced. It isto be understood that other embodiments may be utilized and structuralor logical changes may be made without departing from the scope of thepresent invention. Therefore, the following detailed description is notto be taken in a limiting sense, and the scope of embodiments inaccordance with the present invention is defined by the appended claimsand their equivalents.

Various operations may be described as multiple discrete steps in turn,in a manner that may be helpful in understanding embodiments of thepresent invention; however, the order of description should not beconstrued to imply that these operations are order dependent.

The description may use the phrases “in an embodiment,” or “inembodiments,” which may each refer to one or more of the same ordifferent embodiments. Furthermore, the terms “comprising,” “including,”“having,” and the like, as used with respect to embodiments of thepresent invention, are synonymous. Additionally, the various embodimentsof the present invention may be combined in any suitable manner.

In various embodiments of the invention, hemostatic compositions anddevices, as well as methods for manufacturing such compositions anddevices, are provided. In addition, various embodiments include methodsfor treating hemorrhagic injuries.

In the following description, unless further particularized or otherwisenoted, the term “liquid expandable” is intended to refer to any materialor substance that expands upon contact with a liquid.

In a first aspect, the invention is directed to a hemostatic compositioncomprising a plurality of liquid expandable articles capable ofexpanding upon contact with a liquid. FIG. 1A illustrates selectedaspects of a hemostatic composition in accordance with an embodiment ofthe present invention. As shown, composition 100 includes liquidexpandable articles 102, which are combined to form a plurality ofliquid-expandable articles 104.

FIG. 1B depicts how each liquid-expandable article 102 is capable ofexpanding into an expanded article 106 upon contact with a liquid 108.It follows that the plurality of liquid expandable articles 104 iscapable of expanding into a plurality of expanded articles 110 uponcontact with liquid 108. In various embodiments, liquid 108 may be anaqueous solution, such as a bodily fluid. For example, liquid 108 may beblood.

According to various embodiments of the present invention, composition100 comprises a plurality of liquid-expandable articles 104 that may bemechanically uncoupled from one another and therefore may be capable ofmoving independently from one another. Without limiting the invention toany particular theory, this quality may permit the liquid-expandablearticles 102 to pass through narrow wound openings and to spread intoirregular wound crevices, gaps and fissures.

According to embodiments of the present invention, plurality of liquidexpandable articles 104 may comprise at least 3 liquid expandablearticles 102. In another embodiment, plurality of liquid expandablearticles 104 comprises at least 10 liquid expandable articles 102. Inyet another embodiment, plurality of liquid expandable articles 104comprises at least 50 liquid expandable articles 102. In yet anotherembodiment, plurality of liquid expandable articles 104 comprises atleast 100 liquid expandable articles 102.

In embodiments of the present invention, the volume of eachliquid-expandable article 102 may be from 0.7 mm³ to 7000 mm³. Withoutlimiting the invention to any particular theory, articles in this volumerange may be advantageous because they are small enough to flow freelythrough narrow wound entries, yet large enough to avoid becoming embolivia movement into torn or perforated blood vessels. Articles in thisvolume range are easy to find and retrieve from the wound site at aplace of definitive repair. In addition, liquid-expandable articles 102in this volume range are capable of expanding into expanded articles 106that are large enough to maintain position in a wound cavity in thepresence of a high-flow arterial bleed. In various embodiments, thevolume of each liquid-expandable article 102 may be greater than 1 mm³.In various embodiments, the volume of each liquid-expandable article 102may be greater than 5 mm³. In various embodiments, the volume of eachliquid-expandable article 102 may be greater than 10 mm³. In variousembodiments, the volume of each liquid-expandable article 102 may begreater than 50 mm³. In various embodiments, the volume of eachliquid-expandable article 102 may be greater than 100 mm³. In variousembodiments, plurality of liquid-expandable articles 104 may haveliquid-expandable articles 102 comprising a mixture of sizes.

According to various embodiments, the expanded articles 106 have avolume greater than the liquid-expandable articles 102. In variousembodiments, the average volume ratio of liquid-expandable articles 102to expanded articles 106 is at least 4×. In other embodiments, theaverage volume ratio of liquid-expandable articles 102 to expandedarticles 106 is at least 8×. In other embodiments, the average volumeratio of liquid-expandable articles 102 to expanded articles 106 is atleast 10×. In other embodiments, the average volume ratio ofliquid-expandable articles 102 to expanded articles 106 is at least 12×.

In various embodiments of the present invention, liquid-expandablearticles 102 may be capable of expanding to 80% or greater of theirmaximum expansion capacity in 30 seconds or less following immersion inliquid 108. In other embodiments, liquid-expandable articles 102 may becapable of expanding to 80% or greater of their maximum expansioncapacity in 10 seconds or less following immersion in liquid 108. Inother embodiments, liquid-expandable articles 102 may be capable ofexpanding to 80% or greater of their maximum expansion capacity in 5seconds or less following immersion in liquid 108.

The plurality of liquid-expandable articles 104 may includeliquid-expandable articles 102 of one or more predetermined shapes. Theshape of liquid-expandable articles 102 may influence the ability of thearticles to flow freely through narrow wound entries and to expand,fill, partially fill and conform to a wound cavity. In addition, theshape may assist expanded articles 106 in retaining a desired positionin the wound cavity. In FIG. 1, liquid expandable articles 102 aredepicted as a cylindrical shape. This notwithstanding, the predeterminedshape of liquid expandable articles 102 may include other round,triangular, rectangular, hexagonal conical or octagonal elements. Invarious embodiments, predetermined shapes having multiple projections(e.g., a star) may be used. In other embodiments, the plurality ofliquid-expandable articles 104 may comprise liquid-expandable articles102 with haphazard, random, irregular or jagged shapes. In variousembodiments, plurality of liquid-expandable articles 104 may compriseliquid-expandable articles 102 of two or more predetermined shapes. Inother embodiments, plurality of liquid-expandable articles 104 may haveliquid-expandable articles 102 comprising a mixture of predeterminedshapes and/or irregular shapes.

As shown in FIG. 1C, the predetermined shape of liquid-expandablearticles 102 may define any shape having first major outer surface 112and a second major outer surface 114. In various embodiments, theaverage distance between the outer surfaces may be from 0.5 mm to 20 mm.In various embodiments of the present invention, the average distancebetween a first major outer surface 112 and a second major outer surface114 may be from 1 mm to 10 mm. For such embodiments, the averagedistance between the first major outer surface 112 and the second majorouter surface 114 may be from 2 mm to 5 mm.

According to various embodiments of the present invention,liquid-expandable articles 102 may be substantially in the form of adisk or cylinder. For such embodiments, the average diameter of thefirst major outer surface 112 and the second major outer surface 114 maybe from 1 mm to 20 mm. The average diameter of the first major outersurface 112 and the second major outer surface 114 may be from 5 mm to10 mm. In various embodiments, composition 100 may compriseliquid-expandable articles 102 having the same average diameter or amixture liquid-expandable articles 102 having different averagediameters.

In various embodiments of the present invention, the liquid-expandablearticles 102 may comprise an absorbent material including, but notlimited to, a sponge or fibrous material. In various embodiments of thisaspect, the absorbent material may comprise a polysaccharide such as,but not limited to, cellulose, starch, chitin or chitosan. In variousembodiments of the present invention, liquid-expandable articles 102 maybe biodegradable and/or bioabsorbable. In some embodiments, theliquid-expandable articles 102 may not comprise oxidized cellulose. Invarious embodiments, the absorbent material may comprise syntheticsponges such as, but not limited to, various polyvinyl alcohol (PVA)polymers and derivatives thereof having desirable physical andmechanical properties.

In various embodiments, liquid-expandable articles 102 may comprise acompressed material. For these embodiments, and without limiting thisinvention as to any particular theory, the compressed material, whenhydrated, may rapidly expand in an effort to assume its pre-compressiondimensions. In this way, liquid-expandable articles 102 may storeadditional mechanical energy in a compressed state, as compared to thenon-compressed state, that is released when exposed to liquid 108, thuscausing liquid-expanding articles 102 to quickly expand without usingexogenous gases, liquids or pressure. The absorbent material can becompressed by heat compression or any other suitable method known in theart.

In various embodiments of this aspect, composition 100 may furthercomprise one or more therapeutic agents 116. In an embodiment, theliquid-expandable articles 102 may be impregnated with the one or moretherapeutic agents 116. In another embodiment, the liquid-expandablearticles 102 may be suffused with one or more therapeutic agents 116. Inanother embodiment, the liquid-expandable articles 102 may be coatedwith one or more therapeutic agents 116. In yet another embodiment, theone or more therapeutic agents 116 may be dispersed throughoutliquid-expandable articles 102.

The one or more therapeutic agents 116 may be selected from the groupconsisting of analgesics, steroids, antihistamines, anesthetics,bactericides, disinfectants, fungicides, vasoconstrictors,chemotherapeutic drugs, antibiotics, keratolytics, cauterizing agents,antiviral drugs, epidermal growth factor, fibroblast growth factors,transforming growth factors, glycoproteins, fibrinogen, fibrin,humectants, preservatives, lymphokines, cytokines, odor controllingmaterials, vitamins, and clotting factors.

In various embodiments, the one or more therapeutic agents 116 mayinclude hemostatic agent(s). For example, the one or more therapeuticagents 116 may include chitosan or a derivative of chitosan. In otherembodiments, the one or more therapeutic agents 116 may include kaolin.In other embodiments of the present invention, the one or moretherapeutic agents 116 may be selected from the group consisting ofdiatomaceous earth, silica, clays, minerals, attapulgite, bentonite,zeolite, and bioactive glasses.

According to various embodiments, the one or more therapeutic agents 116may include an inorganic salt. Examples of an inorganic salt include,but are not limited to, a divalent ion selected from the groupconsisting of zinc, copper, magnesium, calcium and nickel, as well asCaO, CaCl2, AgN03, Ca(N03)2, Mg(N03)2, Zn(N03)2, NH4N03, AgCl, Ag20,zinc acetate, magnesium acetate, calcium citrate, zinc citrate,magnesium citrate, magnesium chloride, magnesium bromide, zinc chloride,zinc bromide, calcium bromide, calcium acetate and calcium phosphate.

In various embodiments of the present invention, each liquid-expandablearticle 102 may comprise a marker 118 for identifying the location ofthe articles in a wound and facilitating removal of the articles fromthe wound. For such embodiments, marker 118 may comprise aradio-frequency identification (RFID) tag. In other embodiments, marker118 may comprise a radiopaque material. For example, eachliquid-expandable article may include a radiopaque bead, ball, sphere,wire or strip imbedded within each liquid-expandable article 102. Inother embodiments, liquid-expandable articles 102 may be suffused with aradiopaque material. In yet another embodiment, at least a portion ofeach liquid-expandable article 102 may be coated with a radiopaquematerial.

FIG. 2 illustrates a hemostatic composition in accordance with a furtherembodiment of the present invention. As illustrated, composition 100 maybe in the form of a composite article 202, wherein composite article 202comprises plurality of liquid-expandable articles 104 which have beenfurther compressed together. For such embodiments, composite article 202is capable of quickly disassociating into individual liquid expandablearticles 102 upon contact with liquid 108. Composite article 202 mayadvantageously increase the number and density of liquid-expandablearticles 102 that can be stored/maintained prior to use and allow for anincrease in the number of liquid-expandable articles 102, and ultimatelyexpanded articles 106, that may be delivered into a wound cavity.

According to additional embodiments of this aspect, composition 100 maycomprise a plurality of liquid expandable articles 104 that are coupledto one another to assist with removal of expanded articles 106 from thewound. For example, as illustrated in FIG. 3, composition 100 maycomprise a plurality of liquid-expandable articles 104 that are coupledto one another with a string 302. For example, liquid-expandablearticles 102 may be threaded onto string 302. In other embodiments,liquid expandable articles 102 may be affixed to string 302. Theliquid-expandable articles 102 may be arranged in any suitableorientation on the string 302 so long as string 302 does not impede theexpansion of liquid expandable articles 102 once they are in contactwith liquid 108. For such embodiments, liquid-expandable articles arearranged on string 302 in a way that allows composition 100 to passthrough narrow wound openings and liquid-expandable articles 102 tospread into irregular wound crevices, gaps and fissures.

The attachment of the liquid expandable articles 102 to string 302 aidsin the recovery of expanded articles 106 from the wound cavity, once thepatient reaches a place of definitive care. The caregiver simply needsto pull the string 302 out of the wound cavity and the plurality ofliquid expanded articles 110 is simultaneously removed.

FIG. 4 represents another embodiment of composition 100, in accordancewith the first aspect. In embodiments of this aspect, plurality ofliquid-expandable articles 104 is positioned in a porous, expandable bag402. Bag 402 is employed to facilitate the delivery of liquid-expandablearticles 102 and removal of expanded articles 106. For example, bag 402comprising composition 100 may be applied to a bleeding wound. Once theinjured individual is transported from a field environment to a place ofdefinitive medical care, the bag 402, and thus the expanded articles 106therein, can simply be removed from the wound cavity so that care can beadministered. For such embodiments, bag 402 is sufficiently flexible,porous and expandable to allow composition 100 to pass through narrowwound openings and to allow liquid-expandable articles 102 to expand into expandable articles 106.

In a second aspect, the invention is directed to a medical devicecomprising the composition of the first aspect and an applicator. Theapplicator facilitates the storage, handling and application of thecomposition of the first aspect. Referring now to FIG. 5, wherein ablock diagram illustrating a medical device 500 comprising composition100 in accordance with the present invention, is shown. As illustrated,medical device 500 includes composition 100 positioned in an applicator502. Applicator 502 is employed to facilitate the storage, handlingand/or application of composition 100.

In some embodiments, medical device 500 may further include one or moretherapeutic agents 116 positioned in an applicator 502. In one form, theone or more therapeutic agents 116 may be dispersed throughout device500. For such embodiments, the one or more therapeutic agents 116 may bedetached from composition 100.

FIG. 6 illustrates one form of medical device 500 in accordance withembodiments of the present invention. As shown, applicator 502 includesa receptacle 602 with an output end 604 and a moveable piston 606positioned in receptacle 602. Composition 100 is positioned inreceptacle 602. According to various embodiments, receptacle 602 may bea tube.

In one form, receptacle 602 may comprise a plastic. For example,receptacle 602 may comprise PEEK, PEKK, Polyetherimide (PEI),Polyethersulfone (PES), Polyetherimide (PEI), Polyimide (TPI), FEP, FEP100, ETFE, ETFE 207, ECTFE, PFA or PTFE. In other embodiments,receptacle 602 may comprise a filled plastic or a polymer composite.

Moveable piston 606 is employed to facilitate the ejection of theplurality of liquid-expandable articles 104 from receptacle 602 throughoutput end 604. In an embodiment, moveable piston 606 may be coupled toshaft 608, which has a handle 610. In other embodiments, moveable piston606 may be coupled to a spring or other similar force-applying element.

In accordance with various embodiments, medical device 500 may include avalve 612 coupled to the receptacle 602 at output end 604. Valve 612 isemployed to prevent the premature exit of liquid-expandable articles 102from receptacle 602, as well as impede the flow of liquid 108 intoreceptacle 602 prior to the ejection of liquid-expandable articles.

In various embodiments of this aspect, medical device 500 may beincluded in a kit. A typical kit would comprise medical device 500 andinstructions, such as a product insert or label, directing the user toprepare and administer composition 100.

In a third aspect, the present invention is directed toward a method toeffect rapid hemostatic response and hemorrhage control by applying thecomposition of the first aspect to a bleeding wound.

FIG. 7 is a block diagram depicting a method for treating hemorrhagicinjuries in accordance with embodiments of the present invention. Asillustrated, at 702, composition 100 is applied to a wound. At 704, theplurality of liquid expandable sponges 104 are allowed to inducehemostasis. For example, the plurality of liquid-expandable articles 104may be delivered into a wound cavity, allowed to contact blood withinthe cavity and subsequently expand into expanded articles 106, whichconform to a shape defined by at least a portion of the wound cavity.

Applying composition 100 to a wound may comprise applying thecomposition 100 by hand or by employing medical device 500. If acomposite article 202 is being used, the plurality of liquid expandablearticles 104 may be manually separated to uncouple the liquid-expandablearticles 102 prior to applying the plurality of liquid-expandablearticles 104 to the wound. In various embodiments, composite article 202may disassociate into individual articles upon contact with liquid 108.

Exemplary wounds often arise from, but are not limited to, traumaticaccidents, projectiles from weapons or improvised explosive deviceswhich frequently create small entrance wounds having limited or novisibility to the sites of non-compressible, intra-cavitary bleeding.Such wounds can result in an arterial puncture, a venous puncture, anarterial laceration and/or a venous laceration.

Each wound can have a unique size and/or shape. Often, the extent of thetissue damage cannot be determined until emergent care can be provided.The use of a plurality of liquid-expandable articles 104 allows for thetreatment of several wound types without the need to predetermine thesize and/or shape of a single expandable article (i.e., a singleexpandable plug or pellet) as required to promote hemostasis.

FIG. 8 illustrates a method for treating hemorrhagic injuries in aliving being 812 employing the medical device of FIG. 5. As illustrated,composition 100 may be applied to a wound 802 using medical device 500(FIG. 8A). For such embodiments, plurality of liquid-expandable articles104 may be ejected from receptacle 602 through output end 604. In anexemplary embodiment, wound 802 defines a cavity 804 with an opening 814and a cavity boundary 810 and includes at least one bleeding vessel 806.Once in the wound, liquid-expandable articles 102 contact blood 808 andexpand into a expanded articles 106. As shown in FIG. 8B expandedarticles 106 fill cavity 804 and induce hemostasis.

In a fourth aspect, the invention provides a method of preparing acomposition in accordance with the first aspect of the invention. FIG. 9generically depicts a method of manufacturing composition 100 inaccordance with embodiments of the present invention. At 902,composition 100 may be prepared by forming an absorbant material intoliquid-expandable articles which are combined to form a plurality ofliquid-expandable articles.

For various embodiments, forming the absorbant material into a pluralityof liquid-expandable articles may include compressing the absorbantmaterial into a liquid-expandable material. This may be accomplished,for example, using conventional mechanical compression techniques wellknown to those skilled in the art. In other embodiments, compressing theabsorbant material into a liquid-expandable material may comprisefreeze-drying the absorbant material.

Forming the absorbant material into a plurality of liquid-expandablearticles may include forming it into desirable shapes and sizes. Forsuch embodiments, the liquid-expandable material may be cut using, forexample, a die and press. The absorbant material may also be moldeddirectly into desired shapes and sizes.

In various embodiments, the absorbant material may be formed into aplurality of liquid-expandable articles by extrusion, pelletization,briquetting, tabletting, or other methods familiar to those skilled inthe art. Alternatively, the absorbant material may be mechanicallycrushed into irregular shaped lumps, with desirable size ranges to beseparated out by a classifier.

The absorbant material may be combined with one or more therapeuticagents prior to, during or subsequent to being formed intoliquid-expandable articles. The combining of absorbant material with oneor more therapeutic agent may be performed by impregnating, suffusing,coating or dispersing the on or more therapeutic agents on or throughoutthe absorbant material. In an embodiment, the therapeutic agent may besprayed onto the absorbent material. In another embodiment, theabsorbent material may be soaked in a therapeutic agent solution. Theone or more therapeutic agents may be selected from the group disclosedabove.

In further embodiments of the present invention, a marker may be appliedto each of the liquid-expandable articles. This may be accomplished in anumber of ways. For example, the marker may be imbedded in the absorbentmaterial prior to forming the absorbent material into liquid-expandablearticles. Alternatively, the marker may be imbedded in theliquid-expandable articles during or following a formation step. Inanother embodiment, a radiopaque material may be coated or suffused ontothe absorbent material before, during or after formation of theliquid-expandable articles. For such embodiments, the marker may beselected from the markers disclosed above.

In further embodiments of the present invention, the plurality ofliquid-expandable articles of composition 100 may be further compressedtogether to form the composite article 202.

In a fifth aspect, the invention provides a method of preparing amedical device in accordance with the second aspect of the presentinvention. FIG. 10 depicts a method of manufacturing a medical device500 in accordance with embodiments of the present invention. At 1002, anabsorbent material may be formed into composition 100. Once composition100 has been prepared, it is loaded into an applicator 502 (Block 1004).

The invention is also directed to, in combination, a living being havinga body with a wound defining a cavity with a volume bounded by a surfacethrough which blood is flowing into the cavity, the cavity having anentry opening that is in communication with the cavity; and a pluralityof expandable articles that each have a starting volume and a secondvolume that is greater than the starting volume, the plurality ofexpandable articles with the starting volume deliverable through theentry opening into the cavity and upon being exposed to fluid in thecavity expanded to the second volume, the plurality of expandablearticles within the cavity and expanded to the second volumecollectively inducing hemostasis.

The present invention is directed to a composition comprising aplurality of small, liquid-expandable articles that are configured toinduce hemostasis when contacted with blood and can be applied in deep,irregular wounds. The plurality of liquid-expandable articles possess anability, upon contact with blood, to rapidly expand in unison to form apliable, shapeable, conformable and crevice-filling mass.

Without limiting the invention, this mass may exert gentle mechanicalpressure on the surface of the wound, as well as interact with bloodcomponents to ultimately facilitate the formation of a fluid arrestingcoagulum within the wound cavity. The combination of mechanical pressureand enhanced clotting makes the composition able to curtail bleedingwithout the application of external compression. In other embodiments,liquid-expandable articles may be capable of expanding through aswelling mechanism.

Without limiting the invention, compositions of the invention may beadvantageous for several reasons. Unlike devices that rely on deployinga single hemostatic article or mass (e.g., a single plug, cylinder orsheet), the liquid-expandable articles are sufficiently small to possessa fluid-like flow quality. This quality permits a plurality ofliquid-expandable articles to be fed through narrow wound openings andto spread into irregular wound crevices, gaps and fissures. Availableplugs or sheets are limited by having a fixed dimension, making itdifficult to pass them into a small cavitary wound. On the other hand,the liquid-expandable articles are large enough to avoid performancedrawbacks associated with granules or powders, such as highelectrostatic charge, risk of forming emboli, lack of physical cohesionand difficulties associated with locating and surgically retrievinghemostatic material at a definitive care site.

Another advantage of the liquid-expandable articles as described hereinis the ability to quickly expand into expanded articles. This allows theexpanded articles to quickly fill the wound cavity and provide a nearlyimmediate hemostatic effect without the need for applying any externalcompression. Additional advantages associated with the present inventioninclude improved positioning within the wound, improved tissueapposition and better conformation to intricate wound contours. Thesoft, pliable nature of the expanded articles, in connection withspring-like characteristics, permits the expanded articles to provide agentle outward pressure within the wound cavity, without the need toapply excessive pressure that can compromise perfusion to local tissues.Because the expanded articles conform to the wound cavity, pressure isexerted multidirectionally to address all bleeding points. The abilityto exert outward pressure against and closely conform to surroundingtissue surfaces helps the expanded articles maintain positioning withinin the wound cavity in the face of high flow arterial bleeding anddeformation during transport of the injured person; maximize the contactand application of material at the sources of bleeding; and ensureconstant and gentle, yet effective, compression within the wound cavity(without creating harmful pressure points).

An additional advantage of the present invention is that it is adaptableto different wound sizes and shapes. If an initial dose of composition100 is insufficient to fill the wound, the user may simply add moreliquid-expandable articles 102 until the desired effect is achieved.

Although certain embodiments have been illustrated and described hereinfor purposes of description of the preferred embodiment, it will beappreciated by those of ordinary skill in the art that a wide variety ofalternate and/or equivalent embodiments or implementations calculated toachieve the same purposes may be substituted for the embodiments shownand described without departing from the scope of the present invention.

This application is intended to cover any adaptations or variations ofthe embodiments discussed herein. Therefore, it is manifestly intendedthat embodiments in accordance with the present invention be limitedonly by the claims and the equivalents thereof.

EXAMPLES Example 1

The speed of expansion and degree of expansion of liquid-expandablearticles were measured in saline.

Materials

Composition 1: Regenerated cellulose sponge blocks (3M, Minneapolis,Minn.)(190 mm×109 mm×50 mm) were washed, soaked in a chitosan solution(1% chitosan, 2% acetic acid), compressed and freeze dried. The dry,compressed blocks were die cut into 9.52 mm diameter cylinders.

Composition 2: Regenerated cellulose sponge blocks (3M, Minneapolis,Minn.) (190 mm×109 mm×50 mm) were washed, soaked in a chitosan solution(1% chitosan, 2% acetic acid), heat dried and compressed. The dry,compressed blocks were die cut into 9.52 mm diameter cylinders.

Composition 3: Regenerated cellulose sponge blocks (3M, Minneapolis,Minn.) (190 mm×109 mm×50 mm) were washed, heat dried and compressed. Thedry, compressed blocks were die cut into 9.52 mm diameter cylinders.

Composition 4: Regenerated cellulose sponge blocks (Toray FineChemicals, Chiba, Japan) (190 mm×90 mm×50 mm) were washed, soaked in achitosan solution (1% chitosan, 2% acetic acid), heat dried andcompressed. The dry, compressed blocks were die cut into 9.52 mmdiameter cylinders.

Methods

A large weigh boat with a ruler taped to it was filled with 22 mL ofsaline. The thickness of each sample was measured using calipers. Next,the sample was pressed onto a 27 gauge needle into the center of the topface of the test sample. A timer was started and the needle with thetest sample attached was placed into the saline with the sample at the 0cm mark on the ruler. The length of the sample articles were measure at5, 20, and 60 seconds.

Results

Thickness at Time Intervals

Composition 1

Time (s) 0 5 20 60 Average (cm) 0.55 4.46 4.93 5.07 Stdard Dev 0.10 0.780.30 0.17 (n = 18)Composition 2

Time (s) 0 5 20 60 Average (cm) 0.30 4.45 4.66 4.78 Stdard Dev 0.04 0.360.24 0.25 (n = 48)Composition 3

Time (s) 0 5 20 60 Average (cm) 0.28 3.51 4.63 4.89 Stdard Dev 0.05 1.310.51 0.34 (n = 48)Composition 4

Time (s) 0 5 20 60 Average (cm) 0.34 3.88 4.15 4.29 Stdard Dev 0.05 0.580.43 0.40 (n = 66)

Degree of Expansion

The degree of expansion is defined as the percentage of full expansionat a given time interval. More specifically:Degree of Expansion=t _(i) /t _(f)Where t_(i) is the thickness at some time interval and t_(f) is thefinal thickness. The final thickness is measured at the end of theexperiment, outside of saline.Composition 1

Time 0 5 20 60 Average 0.11 0.86 0.96 0.98 Overall Stdard 0.02 0.14 0.050.02 Dev (n = 16)Composition 2

Time 0 5 20 60 Average 0.06 0.93 0.98 1.00 Overall Stdard 0.01 0.06 0.030.01 Dev (n = 48)Composition 3

Time 0 5 20 60 Ave 0.11 0.71 0.95 1.00 Std 0.17 0.24 0.06 0.01 (n = 48)Composition 4

Time (s) 0 5 20 60 Average 0.08 0.90 0.97 1.00 Overall Stdard 0.01 0.100.05 0.03 Dev (n = 66)

Expansion Factor

The Expansion Factor is defined as a multiple of the original thicknessat a given time interval. More specifically:Expansion Factor=t _(i) /t ₀Where t_(i) is the thickness (cm) and t₀ is the initial dry thicknessmeasurement.Composition 1

Time (s) 0 5 20 60 Average 1.00 8.20 9.23 9.52 Overall 0.00 1.37 1.661.74 Stdard Dev (n = 16)Composition 2

Time (s) 0 5 20 60 Average 1.00 15.23 16.00 16.40 Overall Stdard 0.001.79 1.79 1.73 Dev (n = 48)Composition 3

Time (s) 0 5 20 60 Ave 1.00 10.98 15.24 16.23 (cm) Overal 0.00 5.47 5.195.51 Stdard Dev (n = 48)Composition 4

Time (s) 0 5 20 60 Average (cm) 1.00 11.52 12.39 12.82 Overall Stdard0.00 1.79 1.73 1.81 Dev (n = 66)

Example 2

Composition 1 liquid-expandable articles were tested acutely in a lethalporcine subclavian hemorrhage model against a control of Combat Gauze(CG), the current Special Operational Forces standard of care for severehemorrhage.

Materials

Composition 1 liquid-expandable articles were prepared as described inExample 1. The mean thickness of the liquid-expandable article cylinderswas 4.54 mm with a standard deviation 0.84 mm. Disposable syringes weremodified to create applicators. Briefly, the tips were cut off 60 mlsyringes and vinyl end caps were added. An X-pattern was cut into theend caps to allow passage of articles. One hundred liquid-expandablearticles were loaded into each applicator.

Methods

A modified version of the published Institute of Surgical Research (ISR)swine femoral injury model served as a basis for the subclavian model(Kheirabadi B S, et. al, 4009). Sixteen crossbred Yorkshire castratedswine were used in this study. Prior to transection of the subclavianartery and vein, splenectomies were performed to promote coagulopathy.Wound cavity volume and depth, CO2, O2, mean arterial pressure,hemoglobin concentration, and vessel diameter were measured andrecorded. Primary endpoints of the study included: Hemostasis at 4minutes, hemostasis at 60 minutes, and survival at 60 min. A third-partymedic from the Emergency Medicine Department at Madigan Army Hospitalapplied randomized treatment groups to minimize bias.

To create the injury, the artery, veins and nerve plexus were completelytransected at middle section by the surgeon. The surgeon was blinded tothe hemorrhaging site of the wound. After 30 seconds free bleeding themedic applied the treatment. The average pre-treatment 30-second bloodloss for both treatment groups exceeded 700 cc. The medic was given 4minutes to apply each product. Liquid-expandable articles were appliedusing applicators until the wound was filled to capacity, but noexternal pressure was applied. Per directions on CG packaging, a singleCG dressing was used, backed with Kerlix to fill the wound cavity andexternal pressure applied.

Results

Endpoint Hemostatic Sponges Combat Gauze P-value Hemostasis at 4 6/8 2/80.03 minutes  (75%)   (25%) Hemostasis at 60 8/8 2/8 0.007 minutes(100%)   (25%) Survival at 60 minutes 8/8 3/8 0.026 (100%) (37.5%)

Example 3

Composition 2, 3 and 4 liquid-expandable articles were tested acutely ina lethal porcine subclavian hemorrhage model.

Materials

Liquid expandable articles were prepared as described in Example 1. Themean thickness of the Composition 2 samples was 3.0 mm with a standarddeviation 0.43 mm. The mean thickness of Composition 3 samples 2.7 mmwith a standard deviation 0.30 mm. The mean thickness of Composition 4samples was 3.0 mm with a standard deviation 0.45 mm.

Disposable syringes were modified to create applicators. Briefly, thetips were cut off 60 ml syringes and vinyl end caps were added. AnX-pattern was cut into the end caps to allow passage of articles. Onehundred liquid-expandable articles were loaded into each applicator.

Methods

A modified version of the published Institute of Surgical Research (ISR)swine femoral injury model served as a basis for the subclavian model(Kheirabadi B S, et. al, 4009). Twenty-four crossbred Yorkshirecastrated swine were used in this study. Prior to transection of thesubclavian artery and vein, splenectomies were performed to promotecoagulopathy. Wound cavity volume and depth, CO2, O2, mean arterialpressure, hemoglobin concentration, and vessel diameter were measuredand recorded. Primary endpoints of the study included: Hemostasis at 4minutes, hemostasis at 60 minutes, and survival at 60 min. A third-partymedic from the Emergency Medicine Department at Madigan Army Hospitalapplied randomized treatment groups to minimize bias.

To create the injury, the artery, veins and nerve plexus were completelytransected at middle section by the surgeon. The surgeon was blinded tothe hemorrhaging site of the wound. After 30 seconds free bleeding themedic applied the treatment. The medic was given 4 minutes to apply eachproduct. Liquid-expandable articles were applied using applicators untilthe wound was filled to capacity, but no external pressure was applied.

Results

Number of Number of Test Test Average blood Number of Animals Animalsloss at Animals Hemostatic Hemostatic 30 s post survived at 4 min. at 60min. injury (cc) at 60 min Composition 8/8 8/8 Ave = 8/8 2 568.491 Std =258.39  Composition 6/8 7/8 Ave = 7/8 3 707.798 Std = 161.7  Composition7/8 8/8 Ave = 8/8 4 586.7  Std = 278.3 

What is claimed is:
 1. A hemostatic composition comprising a pluralityof liquid-expandable articles, wherein: individual liquid-expandablearticles of the plurality of liquid-expandable articles comprise amaterial compressed along a first axis, wherein the compressed materialis non-oxidized cellulose; individual liquid-expandable articles aremechanically expandable into expanded articles upon contact with liquidsuch that mechanical expansion of the individual liquid-expandablearticles is principally along the first axis; and individualliquid-expandable articles have a first dimension along the first axis,a second dimension along a second axis perpendicular to the first axis,and the first dimension of the individual liquid-expandable articles isless than the second dimension of the individual liquid-expandablearticles.
 2. The hemostatic composition of claim 1, further comprising:an expandable bag containing the plurality of liquid-expandablearticles.
 3. The hemostatic composition of claim 2, wherein theexpandable bag is porous.
 4. The hemostatic composition of claim 1,wherein the plurality of liquid-expandable articles comprises at leasttwo liquid-expandable articles coupled together.
 5. The hemostaticcomposition of claim 1, wherein an individual liquid-expandable articleis mechanically expandable along the first axis into a correspondingindividual expanded article having a third dimension along the firstaxis and a fourth dimension along the second axis, the first dimensionis less than the second dimension, and the third dimension is greaterthan the fourth dimension.
 6. The hemostatic composition of claim 1,wherein the individual liquid-expandable articles have a cylindricalshape.